This invention is directed to novel chemical compounds and their use in regulating the natural growth or development of plants. In particular, this invention relates to the chemical treatment of plants to alter their natural growth or development for the purpose of enhancing various agricultural or horticultural features of the plants, and also to the control of undesirable vegetation.
It is well known among those skilled in the art of agriculture and horticulture that various features of plant growth can be modified or regulated to produce a variety of beneficial effects.
For instance, certain types of treatment can produce defoliation of a plant in a beneficial manner, i.e., inhibiting further leaf growth while permitting further development of the productive plant parts. As a result, the productive parts demonstrate extra growth, and subsequent harvesting operations are facilitated. Defoliants are particularly useful in flax, cotton, and bean crops, and other crops of a similar nature. Although defoliation results in the killing of leaves, it is not a herbicidal action per se since the remainder of the plant is unharmed. Indeed, killing of the treated plant is undesirable when defoliation is sought, since leaves will continue to adhere to a dead plant.
Another response demonstrated by plant growth regulants is the general retardation of vegetative growth. This response has a wide variety of beneficial features. In certain plants it causes a diminution or elimination of the normal apical dominance, and thus leads to a shorter main stem and increased lateral branching. This alteration of the natural growth or development produces smaller, bushier plants which often demonstrate increased resistance to drought and pest infestation. The retardation of vegetative growth in turf grasses is particularly desirable. When the vertical growth rate of such grasses is lessened, root development is enhanced and a denser, sturdier turf is produced. The retardation of turf grasses also serves to increase the interval between mowings of lawns, golf courses and similar grassy areas.
In many types of plants, such as silage crops, potatoes, sugar cane, beets, grapes, melons and fruit trees, the retardation of vegetative growth results in an increase in the carbohydrate content of the plants at harvest. It is believed that the retardation or suppression of such growth at the appropriate stage of development causes less of the available carbohydrate to be consumed for vegetative growth and results in an enhanced starch and/or sucrose content. Retardation of vegetative growth in fruit trees is demonstrated by shorter branches and greater fullness of shape, and often results in lesser vertical elongation. These factors contribute to the ease of access to the orchard and simplify the fruit harvesting procedure.